package com.hmdp.service.impl;

import cn.hutool.core.util.StrUtil;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.hmdp.dto.Result;
import com.hmdp.entity.ShopType;
import com.hmdp.mapper.ShopTypeMapper;
import com.hmdp.service.IShopTypeService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.List;

import static com.hmdp.utils.RedisConstants.CACHE_SHOP_TYPE_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopTypeServiceImpl extends ServiceImpl<ShopTypeMapper, ShopType> implements IShopTypeService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private ObjectMapper objectMapper;

    /**
     * 查询所有店铺类型
     * @return
     */
    @Override
    public Result queryAllShopType() throws JsonProcessingException {
        String key = CACHE_SHOP_TYPE_KEY;
        //先查redis cache
        String shopTypeJSON = stringRedisTemplate.opsForValue().get(key);
        if (StrUtil.isNotBlank(shopTypeJSON)) {
            //存在，直接返回
            List<ShopType> shopTypeList = objectMapper.readValue(shopTypeJSON,
                    new TypeReference<List<ShopType>>() {});
            return Result.ok(shopTypeList);
        }
        //不存在，查数据库
        List<ShopType> shopTypeList = query().list();
        //不存在，返回错误
        if(shopTypeList == null){
            return Result.fail("店铺类型不存在");
        }
        //存在，写入redis cache
        stringRedisTemplate.opsForValue().set(key,objectMapper.writeValueAsString(shopTypeList));
        //返回结果
        return Result.ok(shopTypeList);
    }
}
